The Emde degradation (also called Emde-reaction or Emde-reduction) is a method for the
reduction of a
quaternary ammonium cation
In organic chemistry, quaternary ammonium cations, also known as quats, are positively-charged polyatomic ions of the structure , where R is an alkyl group, an aryl group or organyl group. Unlike the ammonium ion () and the primary, secondary, ...
to a tertiary
amine
In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...
with
sodium amalgam
Sodium amalgam, with the common formula Na(Hg), is an alloy of mercury and sodium. The term amalgam is used for alloys, intermetallic compounds, and solutions (both solid solutions and liquid solutions) involving mercury as a major component. ...
:
This
organic reaction
Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, mechanistic organ ...
was first described in 1909 by the German chemist Hermann Emde. It was for a long time of great importance in structure elucidation of many
alkaloid
Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids.
Alkaloids are produced by a large varie ...
s, for example that of
ephedrine
Ephedrine is a central nervous system (CNS) stimulant and sympathomimetic agent that is often used to prevent hypotension, low blood pressure during anesthesia. It has also been used for asthma, narcolepsy, and obesity but is not the preferred ...
.
Alternative
reducing agent
In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ).
Examples of substances that are common reducing agents include hydrogen, carbon ...
s exist for this reaction; for instance,
lithium aluminium hydride
Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula or . It is a white solid, discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthe ...
.
See also
* Related reactions are the
Hofmann elimination
Hofmann elimination is an elimination reaction of an amine to form alkenes. The least stable alkene (the one with the fewest substituents on the carbons of the double bond), called the Hofmann product, is formed. This tendency, known as the Hofm ...
and the
von Braun reaction
The von Braun reaction is an organic reaction in which a tertiary amine reacts with cyanogen bromide to an organocyanamide.
An example is the reaction of ''N'',''N''-dimethyl-1-naphthylamine:
These days, most chemist have replaced cyanogen b ...
References
{{Organic reactions
Organic redox reactions
Name reactions
Degradation reactions